package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.*;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.BLOG_LIKED_KEY;
import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 小旭
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {


    @Autowired
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private IUserService userService;

    @Autowired
    private IFollowService followService;

    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = this.query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog -> {
            this.queryBlogUser(blog);
            this.isBlogLiked(blog);
        });
        return Result.ok(records);
    }

    @Override
    public Result queryUserBlog(Long id) {
        //根据博客id查询
        Blog blog = this.getById(id);
        if (blog == null) {
            return Result.fail("博客不存在");
        }
        //添加用户信息
        queryBlogUser(blog);
        //判断用户是否点过赞
        isBlogLiked(blog);
        return Result.ok(blog);
    }

    //判断用户是否点过赞并设置islike的值
    private void isBlogLiked(Blog blog) {
        UserDTO user = UserHolder.getUser();
        if (user == null) {
            return;
        }
        Long userId = user.getId();
        String key = BLOG_LIKED_KEY + blog.getId();
        //判断本用户是否在该帖子的点赞集合中
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(score != null);
    }

    @Override
    public Result likeBlog(Long id) {
        //1.获取登录用户
        Long userId = UserHolder.getUser().getId();
        //2.判断当前用户是否点过赞
        String key = BLOG_LIKED_KEY + id;
        //获取该用户的分数
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        if (score == null) {
            //3.未点过赞，可以点赞
            //3.1数据库点赞数加1
            boolean isSuccess = this.update().setSql("liked = liked + 1").eq("id", id).update();
            //3.2保存用户信息到redis的set集合
            if (isSuccess) {
                stringRedisTemplate.opsForZSet().add(key, userId.toString(), System.currentTimeMillis());
            }
        } else {
            //4.点过赞了，取消点赞
            //4.1数据库点赞数减1
            boolean isSuccess = this.update().setSql("liked = liked  - 1").eq("id", id).update();
            //4.2把用户从redis的set集合中移除
            if (isSuccess) {
                stringRedisTemplate.opsForZSet().remove(key, userId.toString());
            }
        }
        return Result.ok();
    }

    @Override
    public Result queryBlogLikes(Long id) {
        String key = BLOG_LIKED_KEY + id;
        // 1.查询top5的点赞用户 zrange key 0 4
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if (top5 == null || top5.isEmpty()) {
            return Result.ok(Collections.emptyList());
        }
        // 2.解析出其中的用户id
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idStr = StrUtil.join(",", ids);
        // 3.根据用户id查询用户 WHERE id IN ( 5 , 1 ) ORDER BY FIELD(id, 5, 1)
        List<UserDTO> userDTOS = userService.query()
                .in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        // 4.返回
        return Result.ok(userDTOS);
    }

    /**
     * 基于推模式发表博客
     * @param blog
     * @return
     */
    @Override
    public Result saveBlog(Blog blog) {
        // 获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        // 保存探店博文
        this.save(blog);
        //查询该博主的所有粉丝
        List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();
        //推送笔记id给所有粉丝
        Long blogId = blog.getId();
        for (Follow follow : follows) {
            //获取粉丝id
            Long userId = follow.getUserId();

            String key = FEED_KEY+userId;
            //存入redis中（使用sortedSet数据结构）
            stringRedisTemplate.opsForZSet().add(key,blogId.toString(),System.currentTimeMillis());
        }
        // 返回博客id
        return Result.ok(blogId);
    }

    /**
     * 获取关注列表的信息
     * @param max
     * @param offset
     * @return
     */
    @Override
    public Result queryBlogOfFollow(Long max, int offset) {
        //获取当前用户
        Long userId = UserHolder.getUser().getId();
        //查询收件箱
        String key = FEED_KEY+userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        //非空判断
        if(typedTuples.isEmpty()||typedTuples==null){
            return Result.ok();
        }
        //解析数据:blogId、minTime(最后时间戳)、offset
        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0;
        int os = 1;
        for (ZSetOperations.TypedTuple<String> tuple : typedTuples) {
            //获取博客id
            ids.add(Long.valueOf(tuple.getValue()));
            //获取分数(时间戳)
            long time = tuple.getScore().longValue();

            //为minTime初始化
            if(minTime==time){
                os++;
            }else{
                minTime = time;
                os=1;
            }
        }

        //根据id集合查询博客
        String idStr = StrUtil.join(",", ids);
        List<Blog> blogs = query().in("id", ids).last("order by field(id," + idStr + ")").list();

        for (Blog blog : blogs) {
            //查询该blog的博主信息
            queryBlogUser(blog);
            //查询blog是否被本用户点赞
            isBlogLiked(blog);
        }

        //封装上述信息并返回
        ScrollResult sr = new ScrollResult();
        sr.setList(blogs);
        sr.setOffset(os);
        sr.setMinTime(minTime);

        return Result.ok(sr);
    }


    public void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }
}
